Could you tell me about nuclease-resistent oligonucleotides, particularly DNase I-resistant?

There are a variety of ways to make oligonucleotides resistent to nuclease activity. These include the use of phosphorothioated bonds, which can be used to form the entire backbone of an oligo or can be used to "cap" the ends of the sequence. In addition, 2'O-Methyl RNA bases can also be used to make an oligo resistent to nucleases. Finally, phosphorothioate bonds and 2'O-Methyl RNA bases can be combined to create further stability.